User Manual

AS4000 Operations and Maintenance
Section
605-0000-431
5
. Issue 1.6. Date3/2/99
Page 4 of 8 © Copyright Airspan Communications Corporation 1999
Checks to be made at the ST Site
The fault chart over shows a recommended faulting process for ST faults.
Check if ‘side tone’(blow can be heard in earpiece) can be heard on the telephone. If ‘side
tone’ present it suggests that the power has reached the CRU and that the VF wiring to the
phone is OK. This eliminates immediate problems with the ACPSU and Drop Cable.
If ‘side tone’ present the PSU voltage should be checked with a DMM. The value should
nominally be:
Type 1 PSU 36 volts with mains present.
Type 2 PSU 36 volts with mains present or 24 Volts on battery.
If the radio link is not established with the CT the behaviour of the AGC and PC voltage
monitor points will show if a down link has been established and whether the uplink is trying to
acquire. The values of AGC volts should be greater than the -98dBm level recorded on the
CRU characterisation label and should be compared with the original commissioning results to
see if there has been any significant change.
The value of PC volts should be greater than the +21dBm level recorded on the
characterisation label.
AGC/PC State Link State
AGC ramping No downlink see Note 1
AGC stable and in specification Downlink OK
PC 0Volts No attempt to acquire uplink
PC ramping Uplink trying to acquire
AGCs Stable and in specification Link OK (Comms to the CT should be
established under this condition)
Table 6 AGC and PC Volts Indications
Note 1. If there is no downlink it is worth checking that other STs on the same modem shelf
are not experiencing problems , if they are reconsider whether the fault is at the CT. If no other
STs are affected check for path blockage. If the path is clear with no downlink change CRU.
Go to DLP-016.